NEWS113
10
Agorgeouspair ofTricolor Swordtailswith ideal color distribution.
Tricolor Swordtails always exhibit the colors red,black,andwhite.
This tricolor form is very reminiscent of a
BerlinSwordtail.
The high percentage of black in the caudal
finof thismale isdangerous.
Maleswith light-colored swords, like this one,
should be preferred for breeding in order to
avoid cancers.
Koi Swordtail Tricolor "Kohaku"
Tricolor swordtails have been known for
around 15 years, but breeding them is
regarded as exceptionally tricky, as only
relatively few juveniles exhibit an even,
attractive coloration. There are particular
problems with the black coloration, as
specimens with a large amount of black
are inclined todevelopmelanoma,a form
of cancer that, like cancer in humans, is
often fatal for the affected individual. (In
fact it was swordtails suffering from
cancer -whichoriginallyoccurredmainly
in the so-called Berlin cultivated form -
that were the first research animals
available to scientists studying cancer.)
But because this form of cancer can be
inherited the breeder can avoid it by
careful selectionof breeding stock.
Recently some very beautiful Tricolor
Swordtails have been arriving in Europe
from Indonesia. Some specimens are
highly reminiscent of theBerlin cross,but
aTricolor canalwaysbeeasily recognized
by having a white component; this is
because the Tricolor Swordtail was
originally bred from White Swordtails.
Usually these fishes canbe recognizedby
having a blue ring around the iris.White
Swordtails are born red, and it is only as
they grow that they change color. It is
exceptionally difficult to maintain true-
breeding strains of tricolor, bicolor, or
even pure white Swordtails. They are
forever throwing individualsof adifferent
color, e.g. bicolor or even tricolor
individuals in white strains, white or
bicolor in tricolor, andwhite or tricolor in
bicolor
Swordtail breeding is a highly advanced
area of the aquarium hobby. It requires
not only a good knowledge of genetics,
but also hard work and a lot of space.
Swordtail males are very territorial and
oftenonlyoneadultmalecanbekeptper
aquarium. The alternative - numerous
males,or at any ratemore than five -may
make for peace, but then there is no
longer anywayof controllingpairings.
